Chronic pain problems pose a very high cost to individuals and society, and are a major cause of disability among adults during their working years. Although multidisciplinary treatment has been shown to improve disabling chronic pain problems, the processes mediating multidisciplinary treatment effectiveness are not yet clearly understood. Moreover, despite initial improvement, a substantial number of patients return to pretreatment levels of functioning following multidisciplinary treatment for unclear reasons. Cognitive-behavioral theory argues that patient improvement from multidisciplinary treatment is due, at least in part, to changes in patient pain beliefs and coping strategies from maladaptive to adaptive ones. The primary objective of this revised proposal is to test this cognitive-behavioral model in patients participating in multidisciplinary pain treatment by (a) examining the extent to which changes in pain-related beliefs and coping strategies pretreatment through 12-month follow-up are associated with concurrent improvement in physical and psychosocial functioning and (b) determining whether changes in pain beliefs and coping following treatment predict subsequent changes in functioning. To accomplish these aims, patients offered multidisciplinary treatment will be interviewed to assess pain-related beliefs, use of coping strategies, physical disability, psychological functioning, and medical services utilization within 48 hours after being offered multidisciplinary treatment. Patients who accept treatment (n = 273) will be interviewed again when they begin treatment, and again posttreatment. Two assessments prior to treatment will allow for estimates of the stability of the outcome and process variables pretreatment. Eight percent of these patients will be interviewed in multiple waves following treatment (at 2-weeks and 1-, 2-, 3-, 6-and 12-month follow-ups) and 20% will be assessed at 6- and 12-month follow-ups only in order to determine the effects of frequent assessment on the variables studied. Significant others of these subjects will also be asked at each assessment to rate patients on the coping strategies and outcome measures to provide corroborative assessments of the primary variables which may be observed by others. Analyses will be performed to identify the process variables (beliefs and coping strategies) most closely associated with outcome, and to determine whether changes in the process variables precede changes in functioning after treatment. Analyses will also be conducted to determine (a) when relapse after treatment is most likely to occur; (b) whether frequent assessments decrease relapse rates; and (c) whether gender, pain site, pain duration, pain intensity, compensation/litigation issues, depression, and employment status moderate the relationships between the process variables and outcome.